A viscous fluid called photoresist is a crucial substance used in the manufacture of semiconductor circuits.
A photoresist dispenser or pump must be accurate, and must be reliable. A pump failure can not only waste expensive photoresist, but also destroy product by dispersing particles and bubbles into the photoresist and onto semiconductor wafers. Additionally, a pump that is easy to exchange and maintain is favored.
Specifically, the pump improved is that described in U.S. Pat. No. 4,690,621, to inventor Swain. Swain's pump is a pneumatic pump and filter combination. It invites several improvements which are objects of this invention.